Design Of Integrated Temperature Sensor For HF RFID Tags

By about 70 years of development, RFID technology becomes more mature, more and more low cost, and its applications are also greatly expanded, which is accomplished by combination with other techniques, including the combination with a temperature sensor. RFID tags are widely used in various fields of commodity circulation, goods management, personnel tracking, however, it is not applied in the field of environmental monitoring, sensor networks. In order to greatly extend the function of the RFID tag, the RFID tag is integrated with the temperature sensor, which will achieve great success in the human/mechanical temperature monitoring, cold chain logistics and other aspects.Firstly, based on the analysis and comparison of three commonly used temperature sensor circuit principle and the advantages and disadvantages, the paper discusses the HF RFID tag chip integrated temperature sensor architecture. Based on conventional sub-threshold bandgap generation circuit works, the paper innovatively improve the circuit, that is, in the traditional sub-threshold reference circuit adds a negative feedback loop, which greatly increases the loop gain, so the low frequency PSRR is also greatly improved. at SMIC 0.13μm CMOS process simulation.Secondly, through the introduction of the common types of ADC structure, according to the characteristics of these ADC and HF RFID tag chip sensor circuit, this paper focuses consider power consumption, and ultimately choose SAR ADC, and then discusses in detail the structure of the S AR ADC system, each module the working principle, the basic design parameters and non- ideal factors, the innovative design of a low voltage, low-power 10 SAR ADC is presented, under the premise of guaranteeing speed and accuracy, to minimize power consumption. This article is designed circuits are based on SMIC 0.13μ m CMOS process. SAR ADC analog voltage is 1.0V, digital voltage is 0.5V, when 16KS/s sampling rate, ENOB is 9.94 bit, SNR is 62.43 d B, SNDR is 61.62 d B, SFDR is 73.42 d B, power consumption is 273 n W.Finally, the HF RFID integrated temperature sensor chip is completed. the design of the temperature detection accuracy of the temperature sensor circuit can reach ±1℃, in a temperature range [-40℃,80℃], at SMIC 0.13μm CMOS process simulation.